液压机械无级变速器换挡非线性动力学特性分析

摘要

The nonlinear dynamic model of shift process of Hydro-mechanical CVT(Continuously Variable Transmission)is presented in this paper. According to the simulation curves of continuous shift process, the study on the shift control strategy based on the physical parameters and shift time is used to improve the shift quality of a typical condition,which plays a decisive role in the shift quality of the whole shift process. The results show that the shift quality can be improved greatly by the optimization of physical parameters and shift time. The shift control strategy based on the physical parameters is the lower engine rotating speed, smaller load torque, lower pressure of main circuit, the larger flow rate of speed control valves. The shift control strategy based on the shift time is that switch the clutches of shift mechanism firstly, then separate a group of clutches of planet gear mechanism, engage another group of clutches of planet gear mechanism lastly.%建立液压机械无级变速器换挡非线性动力学模型,根据连续换挡过程仿真曲线,对决定变速器换挡品质的一类工况进行基于物理参数和换挡时序的换挡控制策略研究.研究表明通过优化变速器物理参数和换挡时序可大大提高换挡品质.基于物理参数的换挡控制策略为在发动机小转速,外负载小转矩,较小的主油压以及较大的调速阀流量时,可获得较好的换挡品质.基于换挡时序的换挡控制策略为首先切换换挡机构离合器,再切换行星齿轮机构待分离离合器,最后切换行星齿轮机构待接合离合器.